A problem that has at times arisen with the use of vascular stents is reocclusion (restenosis) of the blood vessel after stent implantation. An important factor contributing to restenosis is the injury to or loss of the natural protective lining of endothelial cells on the inner surface of the artery as a result of stent implantation. This loss of the endothelial cell lining denudes the arterial wall, making it vulnerable to thrombosis, infection, scarring, or abnormal tissue growth. Thus, reestablishing a layer of endothelial cells (re-endothelialization) in the stented artery is thought to be important in improving the long-term biocompatibility of the stent. To promote effective endothelialization, however, endothelial cells must migrate from adjacent areas of the artery and adhere onto the surface of the stent.
One proposed approach to promoting re-endothelialization is by providing a surface coated with biologic macromolecules, such as antibodies, to serve as an attachment substrate for endothelial cells. However, in their naturally occurring hydrated state, antibodies and other proteins commonly exist in a complex, folded conformation (i.e., their tertiary structure). This complex, folded conformation of the biologic macromolecules can be disrupted during processing, storage, handling, and/or delivery of the stent, which can result in deactivation of the biologic macromolecules (e.g., due to denaturation from heat or moisture exposure during sterilization of the stent). Thus, there is a need for an improved coating of biologic macromolecules for medical devices.